Would they have access to San's journal, though? Mostly they could be hanging in the background and you could pull them out for, like, RP threads and such. Like Papi Lopez pulled the strings for Santana's apartment behind the scenes -- he's still affecting things even though he doesn't have a journal. The more characters start actually posting to one journal, the more confusing it could potentially get. (I'm trying to figure how to justify guest star journal entries on the NPC journal right now, can you tell? XD)
I should be on AIM either tonight or tomorrow, depending on when I'm on kid duty -- I don't have anything specific in mind, alas, especially since Diego's not either a parent/teacher or a student, but we'll see what would work best for him.